java - 尝试创建随机的 "solar system"

Question

这是 Planet 类:

public class Planet extends CelestialBody {

 private static Random r = new Random();
    private static Star star;

    public Planet(Star star, int orbitRadius, int x, int y){
        name = "PLACEHOLDER";
        radius = Tools.intBetween(Settings.MAX_PLANET_SIZE, Settings.MIN_PLANET_SIZE);
        color = Tools.rObjFromArray(Settings.PLANET_COLORS);
        this.star = star;
        this.orbitRadius = orbitRadius;
        this.x = x; this.y = y;
    }


    public static Planet createNewPlanet(Star star, int orbitRadius){
        int px = (int) (star.x + orbitRadius * Math.cos(Math.toRadians(r.nextInt(360))));
        int py = (int) (star.y + orbitRadius * Math.sin(Math.toRadians(r.nextInt(360))));

        return new Planet(star, orbitRadius, px, py);
    }

    public void render(Graphics g){
        //Draw orbit
        g.setColor(Color.white);
        g.drawOval(star.x - orbitRadius, star.y - orbitRadius, orbitRadius * 2, orbitRadius * 2);

        //Draw planet
        g.setColor(color);
        g.fillOval(x - radius, y - radius, radius * 2, radius * 2);
    }
}

<小时/>

orbitRadius = distance from planet to star (random);

radius = planet's radius (random)

如果您需要更多代码，请在评论中询问，我知道这是一个菜鸟问题，但我就是不明白为什么轨道与行星不对齐。谢谢。

Answer 1

问题出在以下两行:

int px = (int) (star.x + orbitRadius * Math.cos(Math.toRadians(r.nextInt(360))));
int py = (int) (star.y + orbitRadius * Math.sin(Math.toRadians(r.nextInt(360))));

因为您单独调用 r.nextInt(360) 两次，所以每次都会获得不同的随机数。

结果是 x 和 y 坐标针对不同的角度，我认为很清楚为什么这会是一个问题。

解决方案非常简单:调用一次r.nextInt并保存结果:

double randomAngle = Math.toRadians(r.nextInt(360));
int px = (int) (star.x + orbitRadius * Math.cos(randomAngle));
int py = (int) (star.y + orbitRadius * Math.sin(randomAngle));

我认为这应该可以解决问题。